- He knows his stuff. He gave Lopez a music-theory lesson on pentatonics, the five-note scale favored by run-loving singers.

And while Jennifer judges with her "goosies," Harry's often shown looking thoughtfully and seriously at singers before offering his opinions.

- He gives JLO a hard time.

At one point, he turned to her and said, "Jennifer, I will slap you on national television."

At another point, fan after fan came in quivering over being in the presence of Jennifer Lopez, some even crying about being so close to their beloved star. "Keith and I are like bookends up here," Harry cracked.

Many of them had no idea who Harry was. "Can you Google him right now?" one contestant asked a friend in the holding area, and another called him "Tony" Connick.

"You do know who I am, right..." Harry said to one singer. "Chris Isaak."

- He's not afraid to get physical.

When contestant Munfarid Zaidi entered the room on Wednesday, he told Harry: "I read your Wikipedia page every day before going to sleep," which was music to Harry's ears. He quickly rushed the over and gave Zaidi a hug.

"If you blow us away on the first song, I'd like to pick you up and hold you like a baby on the second," promised Harry.

Zaidi did a good job on an Adele song, and Harry rushed over and picked him up, cradling him as he sang some more.

On Thursday's show, Harry hugged Gaddy Basil Foster, simply because he admired his physique. Turns out Foster's singing wasn't great, and Harry wasn't afraid to give him a "no" vote and send him on his way.